Integrated vane for use in wind or water and process for producing the same

ABSTRACT

In an integrated vane  1  for use in wind or water, main blades  3  arranged around an axial shaft  2  of the vane and support blades  4  for joining the main blades to the axial shaft are integrally formed with light and high strength fiber material such as glass fibers and carbon fibers. The main blade is symmetrical or asymmetrical in its cross sectional view and the support blade is symmetrical in its cross sectional view. The upper support blade may be asymmetrical in its cross sectional view and the lower support blade may have an up-and-down reversed shape of that of the upper support blade. A mountain-shaped portion may be formed at the ends of the main blade for reducing noise. The strength of crossing portions between the main and support blade of the vertical axis vane for use in wind or water is thus improved.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an integrated vane for use in wind orwater, in which a vertical axis vane for use in wind or water powergeneration is improved in terms of lightweight, strength andperformance, and a process for producing such an integrated vane for usein wind or water.

(2) Description of the Related Art

In recent years, the generation of electricity by wind or water powerwithout using fossil fuels has been recognized once again worldwide fromthe viewpoints of global protection of the environment, energy securityand economic growth.

As for the generation of electricity by wind power, a horizontal axisvane for use in wind, which has an axial shaft extending in thehorizontal direction relatively to the ground and receives wind with oneor more blades of a propeller type, has conventionally been employed.However recently, a vertical axis vane for use in wind, which has anaxial shaft extending in the vertical direction relatively to the groundand a plurality of blades longer than they are wide extending inparallel with the axial shaft, for example, has appeared (referring to,for example, Japanese Patent Publication No. S56-42751).

The blade in the vertical axis vane for use in wind is fixed to theaxial shaft with one or two support arm(s) extending in the horizontaldirection. The support arm is formed in a thin flat plate-shape in orderto minimize wind resistance upon rotation. The blade extending in thevertical direction is formed in a symmetrical or asymmetricaltwo-dimensional cross sectional shape of a blade. The blades, thesupport arms and the axial shaft constitute a vane (i.e., turbine) foruse in wind.

However, since the conventional blade (main blade) as described aboveis, for example, joined to the support arm with a bolt through a flange,therefore the joining work is complicated, and it is difficult to securethe static or dynamic strength and fatigue strength for the joinedportion between the blade and the support arm, resulting in a problemthat the joined portion is easily damaged by high number of revolutionsbeyond allowance or operation for a long period of time. Further, sincethe joined portion has a large size and large weight, therefore the windresistance during rotation increases and starting stability isdeteriorated, resulting in that the efficiency (i.e., power coefficient)is deteriorated and the noise is increased. Furthermore, when the vanefor use in wind described above is employed as a vane for use in waterfor use in water power generation, problems that the joined portion haspoor strength as described above and the interior of the blade isflooded from a hole for joining the blade arise, therefore the commonuse of a vane for use in wind and for use in water has beensubstantially impossible.

SUMMARY OF THE INVENTION

It is therefore an objective of the present invention to solve the aboveproblems and to provide an integrated vane for use in wind or water anda process for producing such an integrated vane for use in wind orwater, by which the strength of the joined portion between a main bladeand a support arm can be increased, a complicated joining work can beomitted, the joined portion does not have a large size and large weight,the vane can be used not only as a vane for use in wind but also as avane for use in water, and the noise is minimized.

In order to attain the above objective, the present invention is toprovide an integrated vane (i.e., turbine) for use in wind or watercomprising:

-   -   main blades arranged around an axial shaft of the vane; and    -   support blades for joining the main blades to the axial shaft,        wherein the main blades and the support blades are integrally        formed (i.e., formed in one piece) with light and high strength        fiber material such as glass fibers and carbon fibers.

With the construction as described above, since the static or dynamicstrength and fatigue strength for the crossing portion between thestraight blade and the support blade increase, therefore the vane issafe even when the number of rotation is abnormally increased or when weare struck by a typhoon and the vane can stand a continuous operationfor a long period of time. Since the crossing portion can be madecompact, light and to have low resistance and the blades are made oflight and high strength materials, therefore the start performance andefficiency of the vane are improved and the noise is reduced. Sincethere is no joint between both blades and water does not enterthereinto, therefore the vane is useful for use in water.

Preferably, the main blade is symmetrical or asymmetrical in its crosssectional view and the support blade is symmetrical in its crosssectional view.

With the construction as described above, the crossing portion betweenthe main blade and support blade has a symmetrical curved section shapesimilar to the section of the support blade, thereby the strength of thecrossing portion is improved compared to a flat plate-shaped support armof a rectangular section shape, for example. Further, when the frontperiphery of the section-symmetrical support blade faces the flow ofwind or water, the resulting resistance is reduced, and when the rearperiphery of the support blade faces the flow of wind or water, theresulting resistance is increased to give a rotational force, therebyimproving the start performance and efficiency (power coefficient) ofthe vane.

Preferably, the main blade is symmetrical or asymmetrical in its crosssectional view, the upper support blade is asymmetrical in its crosssectional view, and the lower support blade has an up-and-down reversedshape of that of the upper support blade.

With the construction as described above, since the lift generated onthe upper support blade is canceled out by the downward force affectingthe lower support blade, therefore smooth rotation can be attained, thethrust force affecting a bearing of the axial shaft can be reduced andthe lifetime of the bearing increases.

Preferably, a mountain-shaped portion having a height of about half ofthe blade thickness is integrally formed at ends of the main blade inthe axial direction.

With the construction as described above, the mountain-shaped portionreduces or completely attenuates the occurrence of a vortex of wind orwater at the rear of the ends of the blade, thereby attenuating thenoise and preventing the environmental problem from occurring. Since themountain-shaped portion is integrally formed with the main blade,therefore there is no joint, no water enters into the inside, and thevane looks nice.

In order to attain the above objective, the present invention is toprovide a process for producing an integrated vane for use in wind orwater comprising the steps of:

-   -   crossing a preform of a main blade and a preform of a support        blade, each of which comprises at least foamed plastics        material;    -   covering both of the preforms with a light and high strength        bag-shape fiber fabric such as glass fibers and carbon fibers;        and    -   adhering the bag-shaped fiber fabric to the outer surface of        both of the preforms, thereby forming a hard skin with a        plurality of layers of the fiber fabric.

With the construction as described above, since there is no gap on thefiber fabric and both preforms are completely covered with thebag-shaped fiber fabric, therefore the inherent strength of the fiber ismaintained, the main and support blades having high strength areproduced, and especially the crossing portion between the blades havinghigh strength is produced. Therefore, the vane is safe even when thenumber of rotation is abnormally increased or when we are struck by atyphoon and the vane can stand a continuous operation for a long periodof time. Since the crossing portion can be made compact, light and tohave low resistance and the blades are made of light and high strengthmaterials, therefore the start performance and efficiency of the vaneare improved and the noise is reduced. Since there is no joint betweenboth blades and water does not enter thereinto, therefore the vane isuseful for use in water.

Preferably, a sagging portion of the fiber fabric is pushed into thefoamed plastics in the crossing portion between the preform of a mainblade and the preform of a support blade.

With the construction as described above, The outer surface of the mainand support blades and the surface of the crossing portion can besmoothly finely finished, the desired shape of the blades can beprecisely attained, the noise can be reduced due to the decrease in theresistance by the fluid, and the performance and appearance (commercialvalue) are improved. Since a part of the fiber fabric branchlikelyenters into the foamed plastic, therefore the strength of the blades andthe crossing portion can be significantly improved.

Preferably, the preform of a main blade is symmetrical or asymmetricalin its cross sectional view and the preform of a support blade issymmetrical in its cross sectional view.

With the construction as described above, the crossing portion betweenthe main blade and support blade has a symmetrical curved section shapesimilar to the section of the support blade, thereby the strength of thecrossing portion is improved compared to a flat plate-shaped support armof a rectangular section shape, for example. Further, when the frontperiphery of the section-symmetrical support blade faces the flow ofwind or water, the resulting resistance is reduced, and when the rearperiphery of the support blade faces the flow of wind or water, theresulting resistance is increased to give a rotational force, therebyimproving the start performance and efficiency (power coefficient) ofthe vane.

Preferably, the preform of a main blade is symmetrical or asymmetricalin its cross sectional view, the preform of an upper support blade isasymmetrical in its cross sectional view, and the preform of a lowersupport blade has an up-and-down reversed shape of that of the preformof an upper support blade.

With the construction as described above, since the lift generated onthe upper support blade is canceled out by the downward force affectingthe lower support blade, therefore smooth rotation can be attained, thethrust force affecting a bearing of the axial shaft can be reduced andthe lifetime of the bearing increases.

Preferably, a bulging portion having a bulging height which is abouthalf of thickness of a preform of a main blade is formed at ends of thepreform of a main blade in the axial direction and the fiber fabric isadhered on the bulging portion, thereby forming a mountain-shapedportion at ends of the main blade.

With the construction as described above, the mountain-shaped portionreduces or completely attenuates the occurrence of a vortex of wind orwater at the rear of the ends of the blade, thereby attenuating thenoise and preventing the environmental problem from occurring. Since themountain-shaped portion is integrally formed with the main blade,therefore there is no joint, no water enters into the inside, and thevane looks nice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a preferred embodiment of anintegrated vane for use in wind or water according to the presentinvention;

FIG. 2 is a cross sectional view taken along A-A line shown in FIG. 1illustrating a cross sectional shape of a straight blade (main blade);

FIG. 3A is a cross sectional view taken along B-B line shown in FIG. 1illustrating a cross sectional shape of a support blade;

FIG. 3B corresponds to a cross sectional view taken along the B-B lineillustrating a cross sectional shape of another preferred embodiment ofa support blade;

FIG. 4 is a perspective view illustrating a primary stage (a state inwhich a preform of a blade is covered with a fiber fabric) in apreferred embodiment of a process for producing an integrated vane foruse in wind or water;

FIG. 5 is a perspective view illustrating a next stage (a state in whicha fiber fabric is being formed imitating a preform of a blade) in aprocess for producing an integrated vane for use in wind or water;

FIG. 6 is a perspective view illustrating a further next stage (a statein which a fiber fabric is pressed against a preform of a blade) in aprocess for producing an integrated vane for use in wind or water;

FIG. 7 is a perspective view illustrating a state in which a fiberfabric adheres to a preform of a blade;

FIG. 8 is a longitudinal cross sectional view illustrating a state inwhich excess fiber fabric is pushed into the inside of a preform of ablade;

FIG. 9A is a plan view illustrating a preferred embodiment in which amountain-shaped portion for noise control is formed at the end of astraight blade;

FIG. 9B is a front view illustrating a preferred embodiment in which amountain-shaped portion for noise control is formed at the end of astraight blade; and

FIG. 9C is a side view illustrating a preferred embodiment in which amountain-shaped portion for noise control is formed at the end of astraight blade.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the preferred embodiments of the present inventionwill be explained with reference to the attached drawings.

FIG. 1 is a perspective view illustrating a preferred embodiment of anintegrated vane for use in wind or water according to the presentinvention.

In an integrated vane 1 for use in wind or water, which is mainly usedfor wind power generation, straight blades (main blades) 3 longer thanthey are wide arranged in parallel with an axial shaft 2 of the vane 1extending in the vertical direction and support blades 4 as support armsextending in the horizontal direction, which joins the straight blades 3to the axial shaft 2, are integrally formed with each other (formed inone piece) with light and high strength fiber material such as glassfibers (GFRP) and carbon fibers (CFRP).

That is, as an example, one straight blade 3 and two support blades 4arranged up and down are completely integrated with each other withoutany joint. A base end 5 of each support blade 4 is fixed to the axialshaft 2 with joining means (not shown) such as a bolt. As shown in FIG.1, the base end 5 is joined to the axial shaft 2 on an extended line ofa portion of the straight blade 3 near the front periphery 7, while therear periphery 8-side of the base end 5 on an extended line is notched,which is shown with a notch 6.

FIG. 2 is a cross sectional view taken along A-A line shown in FIG. 1illustrating a cross sectional shape of a straight blade 3. Hatching isomitted in FIG. 2. The straight blade 3 has an asymmetricaltwo-dimensional wing shape, a mean line 9 of which curves downward fromthe front periphery 7 of the straight blade 3 (curving downward in FIG.2, that is, curving toward the axial shaft 2 in FIG. 1), meets with achord line 11 at the maximum thickness point 10 of the blade, and curvesupward up to the rear periphery 8. As a result of this shape, theefficiency (i.e., power coefficient) can be increased without changingthe mounting angle of the blade depending upon the flow direction ofwind or water. The shape of the straight blade is disclosed in JapanesePatent Publication No. S56-42751.

FIG. 3A is a cross sectional view taken along B-B line shown in FIG. 1illustrating a cross sectional shape of a support blade 4. The supportblade is symmetrical, in which a mean line 15 agrees with a chord line15 from the front periphery 12 to the rear periphery 13. Although to usea symmetrical blade for a support arm is known as disclosed in JapanesePatent Application Laid-Open No. H7-12045 (a vertical axis vane for usein wind, in which a duct blade is supported by a symmetrical blade), theconstruction of the vane, in which the straight blades 3 and thesymmetrical support blades 4 are integrally formed with each other(formed in one piece), is novel.

Since a symmetrical blade is used for the support blade 4, theresistance arisen when the front periphery 12 receives wind or water inFIG. 1 can be reduced while the resistance arisen when the rearperiphery 13 receives wind or water in FIG. 1 can be increased, therebyrotating the vane 1. Further, since the symmetrical support blade 4 haslarger cross section and circumferential length compared to a flatplate-shaped support blade (not shown) and crosses the straight blade 3with the curved line, therefore the static or dynamic strength andfatigue strength for the crossing portion (i.e., joined portion) 16between the straight blade 3 and the support blade 4 increase, resultingin that the joined portion is not damaged by high number of revolutionsbeyond allowance or operation for a long period of time, because thestraight blades 3 and the support blades 4 are formed integrally witheach other. Further, the joined portion 16 can be made compact, lightand to have low resistance.

FIG. 3B corresponds to a cross sectional view taken along the B-B lineillustrating a cross sectional shape of another preferred embodiment ofa support blade, in which the shape of the support blade 4 isasymmetrical tow-dimensional blade-shape 7. The upper support blade 4shown in FIG. 1 has the asymmetrical shape 7 shown in FIG. 3B, while thelower support blade 4 shown in FIG. 1 has an up-and-down reversed shapeof that of the upper support blade 4. In FIG. 3B, a mean line 18 and achord line 19 are shown.

With the construction as described above, since the lift generated onthe upper support blade 7 is canceled out by the downward forceaffecting the lower support blade (the blade which is formed byreversing the upper support blade 7 up and down), therefore smoothrotation can be attained, the thrust force affecting a bearing (notshown) of the axial shaft 2 can be reduced, and the lifetime of thebearing can be improved.

The axial shaft 2 is preferably a hollow outer rotor and a rotatingshaft of a generator (not shown) is fixed to the end of the outer rotor2, for example. By employing such an outer rotor, the weight of theaxial shaft 2 is reduced, improving the start characteristic of thegenerator. By integrally forming the straight blades 3 and the supportblades 4 with each other by using glass fibers or carbon fibers, thestart characteristic and the efficiency (i.e., power coefficient) can beimproved because of the light weight. Further, because of the integralformation as described above, the strength of the crossing portion 16between the straight blade 3 and the support blade 4 is high. Sincethere is no joint (for example, a hole for joining) between them, thevane according to the present invention can be used not only as a vanefor use in wind but also as a vane for use in water.

FIGS. 4-8 illustrate a preferred embodiment of a process for producingthe integrated vane for use in wind or water as described above.

The process is characterized in that a plurality of layers of the fiberfabric 21 consisting of bag-shaped glass fibers or carbon fibers havingno cut line are adhered to the surface of a preform (i.e., die) 20,which is one size smaller than the straight blade (main blade) 3 or thesupport blade 4.

In the following, the process will be explained in detail in sequence.

As shown in FIG. 4, first a preform (i.e., die) 20 is formed by using ahard core part 22, 23 for reinforcing and determining the position,which made of, for example, synthetic resin and a foamed styrol 24 whichis light and compressible material for retaining the shape.

The core parts 22 and 23 of the preform 20 are penetratingly arranged inthe length direction in the preform 25 of the straight blade (mainblade) and the preform 26 of the support blade, respectively, and eachcore part 23 is fixed crossing the core part 22. The center of each corepart 22, 23 approximately agrees with the center of the maximumthickness of the preform of the corresponding blade 3, 4 in FIG. 1. Thefoamed styrol 24 surrounds the core part 22 or 23 and is formed one sizesmaller than the straight blade 3 or the support blade 4 with a shapesimilar to the straight blade 3 or the support blade 4.

The preform 20 consisting of the preform 25 of the straight blade andthe preform 26 of the support blade is covered with a large-sized fiberfabric 21 consisting of bag-shaped glass fibers or carbon fibers. Asshown in an enlarged figure in a circle C in FIG. 4, in the fiber fabric21, for example, fibers are compactly woven in two-dimensional directionlike a normal cloth. It may be possible to weave the fibers inthree-dimensional direction instead of two-dimensional direction so asto increase the bonding strength. The fiber fabric 21 can be mixed with,for example, thermoplastic synthetic resin. The fiber fabric 21 may beas thin as about 0.2 mm per sheet.

The thin fiber fabric 21 is formed to be a big bag and as shown in FIG.4 the preform 20 is covered with a sheet of the bag-shaped fiber fabric21 in the vertical direction in the figure with the length direction ofthe preform 25 of the straight blade being arranged in the verticaldirection. The preform 20 is completely covered with the bag-shapedfiber fabric 21. In FIG. 4, an opening 27 of the bag-shaped fiber fabric21 is shown.

On such a condition, as shown in FIGS. 5-7, the fiber fabric 21 ispressed against the outer surface of the preform 20, that is, the outersurface of the foamed styrol 24 by means of vacuum evacuation (notshown) or the like and adhered thereto with an adhesive or the like. Asshown in FIG. 5, for example, the preform 21 is entered into between thetwo preforms 26 of the support blade from the front periphery 29 of thesupport blade with bending the fiber fabric 21 in a U-shape 30.Preferably, the preform 21 is adhered to the preforms 25 and 26 from theperipheries 28 and 29, respectively, with bending the fiber fabric 21 ina U-shape 30.

Alternatively, the fiber fabric 21 is moved toward the preform 25 of thestraight blade along the length direction of each preform 26 of thesupport blade between the two preforms 26 situated up and down, forminga gap 33 between the two preforms 26, and the preforms 25 and 26 arecovered with the fiber fabric 21 as shown in FIGS. 6 and 7.

In the process of such a work described above, especially a sag easilyoccurs at the crossing portion (i.e., joined portion) 31 between thepreforms 25 and 26. Therefore, as shown in FIG. 8 (the core part 22, 23being not shown), the sagging portion 32 of the fiber fabric 21 ispushed into the inside of the foamed styrol 24 with a spatula or thelike. For a portion where a sag occurs besides the crossing portion 31,such a sag is pushed into the inside of the foamed styrol 24. Such apushing work can be easily securely curried out by pushing the saggingfiber fabric 21 into a rent of the foamed styrol 24 after the foamedstyrol 24 is broken to make the rent. Thereby, the surface of each blade3, 4 (in FIG. 1) can be smoothly finely finished without the saggingportion of the fiber fabric 21 protruding on the outer surface of eachblade 3, 4. Further, a part of the fiber fabric 21 branch likely entersinto the inside of the foamed styrol 24, thereby improving the strengthof the blades.

It may be avoided as mush as possible that the sag of the fiber fabric21 is cut off with a scissors or the like. In the event that the fiberfabric is cut, the mechanical strength of the blades 3, 4 and thecrossing portion 16 (in FIG. 1) may be deteriorated. If the saggingportion is pushed into the inside of the foamed styrol 24 as describedin the preferred embodiment, such a deterioration in the mechanicalstrength can be prevented from occurring. Since the fiber fabric 21 maybe as thin as 0.2 mm or so, therefore the pushing work of the saggingportion of the fiber fabric 21 into the inside of the foamed styrol 24can be easily carried out.

The working process illustrated in FIGS. 5-8 per a sheet of the fiberfabric 21 is repeated. The number of layers of the fiber fabric sheetsmay be about 3 to 8. The pushing-in work of the sagging portions 32 (inFIG. 8) can be carried out per a sheet of the fiber fabric 21 ortogether after adhering all of the sheets of the fiber fabric 21. Theadhesion work can be effectively carried out with a thermosettingadhesive such as an epoxy adhesive by heating. This heating is carriedout after all of the sheets of the fiber fabric 21 are adhered.

At the crossing portion 31 between the preforms 25 and 26, the fiberfabric 21 may be adhered in a curved-shape 34 a little. The crossingportion 31 may be formed having a curved-shape in advance. The crossingportion 16 between the blade 3 and blade 4 having a curved-shape makesthe strength of the crossing portion 16 large.

Preferably, both of the ends 35 up and down of the preform 25 of thestraight blade is formed having a curved-shape a little so as to give acurve-shaped bulging portion (i.e., mountain-shaped portion; explainedlater on), thereby reducing noise arisen by the resistance due to windor water. Preferably, a notch 6 is formed at the base end of the preform26 of the support blade (i.e., the joint with the axial shaft 2) asshown in FIG. 1.

A plurality of the sheets of the bag-shaped fiber fabric 21 constitute ahard and rigid skin 36 (in FIG. 8). After the adhesion of a plurality ofthe sheets of the fiber fabric 21 is completed, a waterproof coating isapplied, thereby completing an integrated formed body 37.

Preferably, the preform 20 is completely covered with a bag-shaped fiberfabric 21 without a gap. In the event that the bag is too large leavinga large rest of the fiber fabric 21, it is possible to cut the fiberfabric 21 on the rear periphery 38, 39-side (in FIG. 5) of each preform25, 26. In such a case, however, the fiber fabric 21 must be adhered onthe rear periphery 38, 39-side without a gap right and left, and up anddown. Further, after a plurality of the sheets of the fiber fabric 21are adhered to the preform 20, a fiber fabric having a rectangle shapeor a curved-shape may be further adhered thereto in terms of finishing.

Thus completed integrated formed body 37 (in FIG. 7) is symmetrical inthe up-and-down direction. Three pieces of the integrated formed body 37are equivalently fixed to the axial shaft 2, thereby completing anintegrated vane 1 for use in wind or water for use in wind or waterpower generation as shown in FIG. 1.

The support blades 4 up and down may be fixed to a round-shaped flangeplate (not shown) instead of the long axial shaft 2 so that the centerof the flange plate can be rotatably supported by a short axial shaft.The center of the axial shaft 2 or the center of the flange plate alignswith the axis.

The number of the straight blades 3 is determined according to thedesired amount of electric generation. Only one straight blade 3 may bepossible. Only one support blade 4 situated at the middle of thestraight blade 3 in the vertical direction may be possible. The shape ofthe support blade 4 may be a flat plate shape having a rectangle in itscross section or an asymmetrical shape as shown in FIG. 3B instead of asymmetrical shape in its cross section. Further, although the efficiencyis deteriorated, the straight blade 3 may be a two-dimensionalsymmetrical blade. Further, a curved blade (not shown) may be usedinstead of the straight blade 3. Furthermore, the main blade 3 orsupport blade 4 may be a three-dimensional blade.

The integrated vane 1 for use in wind or water may be disposed, forexample, on a side wall of upper location of a tall building with theaxial shaft 2 of the integrated vane 1 being set in the horizontaldirection. Further, the integrated vane may be used for a thermalconverter for converting water to hot water. If the vane 1 is used as avane for use in water, each straight blade 3 is entered into water fromthe end of the length direction thereof with the axial shaft being heldalong the vertical direction. The length of entering of the straightblade 3 into water may be determined according to the desired amount ofelectric generation or the flow of water.

Further, for use in water, the cores 22, 23 of the preforms 25, 26 maybe made of light metal such as aluminum alloy. Another kind of foamedplastic having a property of shape-retainer (property of not being verymuch dented when pushed while being broken when strongly pushed) may beemployed instead of the foamed styrol 24 (i.e., polystyrene formedhaving air bubbles therein) of the preform 20. The preform 20 may beformed only with the foamed styrol 24 without using the cores 22, 23. Inthe process for producing an integrated vane 1 for use in wind or wateras described above, the foamed styrol 24 and the core 23 is left behindinside the skin consisting of a plurality of the sheets of the fiberfabric 21, however, when the ends of the length direction of each blade3, 4 is formed at last, the foamed styrol 24 or the core 23 may be takenout before the ends of the blade are formed.

FIGS. 9A-9C are a view illustrating a preferred embodiment in which amountain-shaped portion (having its length of about half of thethickness of the blade) 41 for noise control is formed at the end of astraight blade (main blade) 3.

FIG. 9A is a plan view of the straight blade 3, FIG. 9B is the frontview and FIG. 9C is the side view. The mountain-shaped portion 41 has ashape that the cross section shape of the blade is cut by about halfalong the chord line 11 (in FIG. 2) and has an about symmetrical shaperight and left in a front view thereof as shown in FIG. 9B. That is, theblade section of a straight blade is cut by half thereof, thus obtainedcross sectional shape is made to be a longitudinal cross section of themountain-shaped portion 41, and the top 42 of the longitudinal crosssection is smoothly curvedly connected to the side 43 of the straightblade 3.

As shown in FIG. 9B, the top 42 of the mountain-shaped portion 41 issmoothly curvedly formed from the front end to about the middle of theblade (in FIG. 9A) in the thickness direction and the edge line portionof the top 42 gradually becomes thin as the width of the mountain-shapedportion 41 becomes narrow from the middle to the rear end in FIG. 9A.The front end 44 and rear end 45 of the mountain-shaped portion 41 aresmoothly continued to the front end 7 and the rear end 8 of the straightblade 3, respectively. The mountain-shaped portion 41 is formedintegrally (i.e., formed in one piece) with the straight blade 3 withthe fiber fabric 21.

The ratio of the thickness of the mountain-shaped portion 41, that is,the maximum height (i.e., maximum blade thickness) H relative to theblade chord length is restricted to some extent by the blade thicknessof the straight blade 3 and is preferably about (24-34%)/2, that is,about 12-17%. Here, the (24-34%) is the blade thickness of the bladesection before forming the mountain-shaped portion 41 and the reason ofdividing by 2 is based on that the blade section is approximatelysymmetrical (if it is a symmetrical blade section, the factor isprecisely ½). These optimum ranges are based on the experiments. Acondition deviated from these optimum ranges is also efficient for noisecontrol.

The mountain-shaped portion 41 reduces or completely attenuates thenoise due to the resistance by wind or water upon rotation of the vane.This is because the mountain-shaped portion 41 reduces or completelyattenuates the occurrence of a vortex of wind or water at the rear ofthe ends of the blade.

In a process for producing an integrated vane having the mountain-shapedportion 41 as shown in FIGS. 9A-9C, for example, a bulging portion(mountain-shaped portion) one size smaller than the mountain-shapedportion 41 (that is, smaller than the mountain-shaped portion 41 by thethickness of the fiber fabric 21) is formed by using foamed styrol andis joined with the ends up and down of the foamed styrol 24 of thepreform 25 of the straight blade shown in FIG. 4, or the foamed styrol24 is provided integrally with a bulging portion (mountain-shapedportion) separately from the core 22 so as to form the preform 20,thereafter a plurality of layers of the fiber fabric 21 are adhered tothe preform 20 by using a method as shown in FIGS. 4-8, thereby themountain-shaped portion 41 formed integrally with the straight blade(main blade) 3 can be easily precisely formed.

The aforementioned preferred embodiments are described to aid inunderstanding the present invention and variations may be made by oneskilled in the art without departing from the spirit and scope of thepresent invention.

1-4. (canceled)
 5. A process for producing an integrated vane for use inwind or water comprising the steps of: crossing a preform of a mainblade and a preform of a support blade, each of which comprises at leastfoamed plastics material; covering both of the preforms with a light andhigh strength bag-shaped fiber fabric; and adhering the bag-shaped fiberfabric to the outer surface of both of the preforms, thereby forming ahard skin with a plurality of layers of the fiber fabric.
 6. The processfor producing an integrated vane for use in wind or water according toclaim 5, wherein a sagging portion of the fiber fabric is pushed intothe foamed plastics in a junction portion between the preform of themain blade and the preform of a support blade.
 7. The process forproducing an integrated vane for use in wind or water according to claim5, wherein the preform of a main blade is symmetrical or asymmetrical inits cross sectional view and the preform of a support blade issymmetrical in its cross sectional view.
 8. The process for producing anintegrated vane for use in wind or water according to claim 5, whereinthe preform of a main blade is symmetrical or asymmetrical in its crosssectional view, a preform of an upper support blade is symmetrical inits cross sectional view, and the preform of a lower support blade hasan up-and-down reversed shape of that of the preform of an upper supportblade.
 9. The process for producing an integrated vane for use in windor water according to claim 5, wherein a bulging portion having abulging height which is about half of thickness of a preform of a mainblade is formed at ends of the preform of a main blade in the axialdirection and the fiber fabric is adhered on the bulging portion,thereby forming a protruding portion at ends of the main blade.
 10. Theprocess for producing an integrated vane for use in wind or wateraccording to claim 6, wherein the preform of a main blade is symmetricalor asymmetrical in its cross sectional view and the preform of a supportblade is symmetrical in its cross sectional view.
 11. The process forproducing an integrated vane for use in wind or water according to claim6, wherein the preform of a main blade is symmetrical or asymmetrical inits cross sectional view, a preform of an upper support blade issymmetrical in its cross sectional view, and the preform of a lowersupport blade has an up-and-down reversed shape of that of the preformof an upper support blade.
 12. The process for producing an integratedvane for use in wind or water according to claim 6, wherein a bulgingportion having a bulging height which is about half of thickness of apreform of a main blade is formed at ends of the preform of a main bladein the axial direction and the fiber fabric is adhered on the bulgingportion, thereby forming a protruding portion at ends of the main blade.13. The process for producing an integrated vane for use in wind orwater according to claim 7, wherein a bulging portion having a bulgingheight which is about half of thickness of a preform of a main blade isformed at ends of the preform of a main blade in the axial direction andthe fiber fabric is adhered on the bulging portion, thereby forming aprotruding portion at ends of the main blade.
 14. The process forproducing an integrated vane for use in wind or water according to claim8, wherein a bulging portion having a bulging height which is about halfof thickness of a preform of a main blade is formed at ends of thepreform of a main blade in the axial direction and the fiber fabric isadhered on the bulging portion, thereby forming a protruding portion atends of the main blade.
 15. The process for producing an integrated vanefor use in wind or water according to claim 10, wherein a bulgingportion having a bulging height which is about half of thickness of apreform of a main blade is formed at ends of the preform of a main bladein the axial direction and the fiber fabric is adhered on the bulgingportion, thereby forming a protruding portion at ends of the main blade.16. The process for producing an integrated vane for use in wind orwater according to claim 11, wherein a bulging portion having a bulgingheight which is about half of thickness of a preform of a main blade isformed at ends of the preform of a main blade in the axial direction andthe fiber fabric is adhered on the bulging portion, thereby forming aprotruding portion at ends of the main blade.